数字钻孔摄像在小浪底帷幕灌浆检测孔中的应用

Application of digital borehole camera to quality test boreholes for grout curtain in Xiaolangdi Water Control Project

为了评价帷幕灌浆效果,将数字钻孔摄像技术应用到小浪底水利枢纽3号灌浆洞3个灌浆质量检查孔中。通过数字钻孔摄像得到的孔壁图像资料,对钻孔内发育的节理裂隙、破碎带和砂浆充填情况进行了分析研究,结果表明:灌浆时浆液在外压下,主要沿连通性较好、延伸较远的裂隙向孔外岩体渗透。与渗流路径相连通的裂隙或延伸较短的裂隙,被浆液直接充填凝固后形成水泥结石。与渗流路径没有连通的裂隙则被忽略,或在灌浆压力下劈裂而部分充填,造成全充填、半充填和砂浆流出等几种充填效果;破碎带充填与否主要与破碎带的规模、性质和与灌浆洞连通性有关。小浪底水利枢纽3号灌浆洞内的灌浆效果是明显的;将数字钻孔摄像技术应用于检查帷幕灌浆质量,分析灌浆浆液渗流路径,也是可行的。

In order to appraise the quality testing of grout curtain, digital borehole camera technology is applied to three boreholes of the grouting gallery No.3 in Xiaolangdi Water Control Project. This paper introduces the basic theory and analytical method of digital borehole camera technology, presents some typical borehole-wall images of joints, cracks, fracture zones and crack filler of mortar in the three boreholes and further analyzing. It is concluded that：（1）The grout is impelled by grout pressure and seeped towards the rockmass around the boreholes mainly along fractures and cracks which have good connectivity and extension in the fracture network The fractures are filled who open to the main seepage path cracks and those are neglected who not open to main seepage path or partly filled after flerried under grout pressure. As a result of our exploration, three different filling situations of all-filled, partly-filled and run-out mortar are observed in borehole wall. （2） The filling of fractured zones depend on the size, property and connectivity with grout holes. These findings of the application have led the author to the conclusion that： the enhancement in rockmass integrity by grout curtain project in the grouting gallery No.3 of Xiaolangdi Water Control Project is obvious. The application of the digital borehole camera technology to quality test of grout curtain by boreholes exploration is feasible.